NEW ORLEANS — A federal jury handed Merck & Co. a major victory on Friday, clearing the drug maker of any responsibility in the death of a 53-year-old Florida man who had a heart attack after taking its once popular painkiller Vioxx for less than a month.

This was the second court victory for Merck, and the first in a federal court. The company had argued in this case that plaintiff lawyers never proved any link between Vioxx and the heart attack Richard “Dickey” Irvin suffered in 2001. Merck’s lawyers contended Irvin’s age, gender and diet all put him at risk for heart attacks.

It was also the second time jurors heard the case brought by Irvin’s family. In Houston, where the case was heard in November and December because of damage from Hurricane Katrina, jurors were unable to reach a verdict. Merck won a state case in New Jersey last year, while it lost one in Texas.

Irvin’s widow, Evelyn Irvin Plunkett; the youngest of their three daughters, Ashley Irvin; and their only son, Richard Irvin III, all testified that Irvin’s health had been excellent up to his heart attack.

Plunkett left the courtroom in tears without talking to reporters.

“Obviously the family is very upset,” said her attorney, Andy Birchfield.

He said the biggest problem was Judge Eldon Fallon’s ruling, shortly before the trial, that two of their experts — a cardiologist and a pathologist — could not testify that Vioxx was to blame for Irvin’s heart attack. They were experts in their fields, but not about Vioxx, the judge ruled.

“With all due respect, we think that (ruling) was error,” said Birchfield. He said he would be talking with Plunkett about whether to appeal.

Phil Beck, a lawyer for Merck said he believes the verdict indicates the jury found “that the Merck scientists lived up to their legal and ethical responsibilities when manufacturing and marketing Vioxx and making the decision to take Vioxx off the market.”

The jury deliberated for 3 hours and 40 minutes, the shortest period of any of the four juries yet in Vioxx-related cases.

Observers said the verdict was a clear victory for Merck, but the company will face more formidable cases later on this year with plaintiffs who took Vioxx for 18 months or longer. Merck removed the drug from the market after a study showed it doubled patients risk of heart attacks and strokes after 18 months.

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Still, Howard Erichson, a professor at Seton Hall Law School, said this verdict may keep plaintiff lawyers from filing short-term use cases. It may also help Merck because the judge overseeing all the federal cases has said he wants to discuss a settlement after trying the first four.

“To the extent that ultimately there is a wide settlement, this win plays in Merck’s favor,” said Erichson.

So far, about 9,600 cases related to Vioxx have been filed.

Analysts have estimated Merck’s liability could reach $50 billion. So far the company has set aside almost $1 billion for legal fees.

On the conference call, Merck senior vice president and general counsel Kenneth Frazier, reiterated that the company intends to try each case individually.

Frazier also said that the study that caused Merck to withdraw Vioxx may give plaintiff lawyers data to use in their cases, but they still face the burden of proving that the drug was a cause of the heart attack or stroke. He noted heart attacks are common and have many causes, including high blood pressure.

Plaintiff lawyers had been buoyed by the prospect of new evidence that showed Merck failed to disclose information about three additional heart attacks suffered by patients in a study known as VIGOR when it was published by the New England Journal of Medicine. The additional heart attacks were disclosed to the U.S. Food and Drug Administration.

The lawyers believed the failure to disclose would signal that Merck was trying to cover up negative news. Not only did plaintiffs have a videotaped deposition of the Journal’s executive editor chastising the author’s actions, but one of the authors of the study was a key witness for Merck, Dr. Alise Reicin.

But in a conference call, Beck said the verdict clearly showed the plaintiffs were wrong in their estimation of Reicin and the issue. He noted their cross examination of Reicin was longer than the jurors’ deliberations.

The case could be the first indication of outcomes in federal court, generally seen as more disciplined and friendly to businesses than state courts.